A review on high-cycle fatigue size effect of selective laser melted metals

In recent years, many scholars have carried out relevant work to solve the issue of fatigue size effect in additive manufacturing (AM) specimens. This paper provides a comprehensive review and summary of the size effect in AM metals under high-cycle fatigue conditions. The factors affecting different defect characteristics of AM materials and the size distribution of critical defects are systematically collected and organized. According to two research perspectives, the fatigue size effect in AM metals can be categorized into statistical size effect and stress size effect. Subsequently, the generation mechanisms of these two types of size effects are respectively described, followed by a summary of the theoretical model applicable to AM metal fatigue size effect. Finally, several suggestions for further research on the size effects of AM metal fatigue are proposed.